Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2006
Publication Date: February 1, 2007
Citation: Rao, S.C., Northup, B.K., Phillips, W.A., Mayeux Jr, H.S. 2007. Improving forage production in bermuda grass paddocks with novel cool-season annual legumes. Crop Science. 47:168-173. Interpretive Summary: In some regions of the U.S., legumes are often inter-seeded into perennial grass pastures in order to increase the length of the grazing season, improve forage quality or forage production, and provide nitrogen to the grass. This practice is not common in the southern Great Plains, probably because it has not been shown to be practical and suitable legumes may not be available. We inter-seeded two annual cool-season legumes, grass pea and lentil, into a bermudagrass pasture in early spring and measured the effects on forage production and quality. One of the two legumes, grass pea, was well adapted and increased both forage quality and production in comparison to unfertilized bermudagrass or bermudagrass fertilized with a relatively low rate of nitrogen (45 lb N per acre). The other legume, lentil, was not well adapted and had little effect on forage production or quality. Results indicate that inter-seeding legumes into warm-season perennial grasses like bermudagrass is a useful practice for the region, especially if fertilizer management is designed to meet the needs of both the legume and the grass.
Technical Abstract: Inter-seeding non-traditional, cool-season legumes into Bermudagrass [Cynodon dactylon (L.) Pers.] paddocks was evaluated as an approach to increasing the quality and duration of forage production and replacing a portion of the nitrogen (N) fertilizer required in the southern Great Plains. We compared the effects of inter-seeding either grass pea (Lathyrus sativa L. cv. AC-Greenfix) or lentil (Lens cilinaris Med. cv. Indianhead)with N fertilizer rates of 0, 45, or 90 kg N ha-1. All plots recieved 60 kg P2O5 ha-1 in early March. The legume and fertilizer treatments were imposed in mid March during 2001, 2002, and 2003. Forage samples were clipped from 0.25 m-2 quadrats on five sampling dates between May 1 and July 15 each year. Yield, N concentration, species composition and in vitro digestible dry matter (IVDDM) were determined. Year, sampling date, and treatment showed significant (P< 0.05) effects as did the 2-way interactions between all three factors. Total, end-of-season standing dry matter of Bermudagrass and grass pea was 5550 kg ha-1, which was similar to biomass production with 45 kg N ha-1 (5305 kg ha-1) and less than that produced with 90 kg N ha-1. End-of-season standing crop with lentil was similar to the non-fertilized Bermudagrass, but N and IVDDM concentrations of the forage mixture were intermediate between the higher N rates. Although additional studies are needed to optimize management for the inter-seeded legumes, we conclude that this practice can improve the quality and duration of Bermudagrass forage production in this region.